A lithium ion secondary battery is used as power supplies for smart phones or personnel computers, and as power supplies for automobiles. In the batteries used for these applications, investigations aimed at improving various characteristics, such as increase in power, increase in energy density, improvement of cycle characteristics or rate characteristics, are made.
There is a technology of using an additive as a technology which tries to improve characteristics of a lithium ion secondary battery in terms of an electrolytic solution. For example, Patent Document 1 proposes a technology in which an attention is given to an effect derived from anhydrides of sulfonic acid and carboxylic acid that a reductive decomposition of a non-aqueous solvent in charging is suppressed, by using this effect, a reduction in a high-load discharge capacity after being stored at 60° C. is suppressed. In Patent Document 2, monofluorophosphate and/or difluorophosphate, and sulfobenzoic acid are used in combination in order to improve low-temperature discharge characteristics and cycle characteristics. Patent Documents 3 and 4 propose a technology of suppressing a decomposition reaction of an electrolyte with use of sulfobenzoic anhydride or the like to enhance chemical stability of an electrolytic solution.
Patent Document 5 discloses a technology of suppressing deterioration of storage characteristics under high temperature by adding benzoic anhydride, phthalic anhydride or maleic anhydride to an electrolytic solution of a non-aqueous electrolytic solution secondary battery. Patent Document 4 proposes a technology in which low-temperature cycle characteristics of a battery are improved and chemical stability of an electrolytic solution is enhanced by using carboxylic anhydride such as succinic anhydride, glutaric anhydride or maleic anhydride in combination with a specific electrolyte salt.